Electric Chair

An electric chair AND LEDs, oh my. However, this instructable is more about a demonstration on the coefficient of thermal expansion between different materials. Before I lose your attention, did I say that there was going to be molten glass, LEDs, AND an electric chair ( in this case, a small chair like object with current running through it).

I am encasing a very, very simple circuit in molten glass that brings up a few interesting things:

1. Glass is a conductor when molten, something you do not hear about too often in your electronics books, but then again, how often does this situation come into play.

2. Glass is an insulator when not molten, though technicality speaking glass is never completly solid. The molecules are still ever so slightly moving, meaning that your kitchen glass will eventually slump. However, this slumping may take a couple thousand years to do that.

3. Copper can be combined with molten glass. This ia a loose statement with way too many parameters for why this can and cannot work.

If you are inclined to get your geek-on, I will put a bit more info on another page in this instructable about the science behind combining these materials in this situation.

Making a Simple Circuit With Copper Wire

I used copper wire that was twisted and crimped to make part of the simple circuit. Since this will be encased in 2000 degree molten glass, I am pretty positive that solder won't hold up too well.

I am just guessing, but things like IC chips and mosfets won't hold up to 2000 degrees either.

I did not want the copper too thick because there is a good chance the glass will crack. This will be explained later.

Time for the Hot Glass

This is a series of photos showing one of the ways I tried to encase the copper wire form in glass.

The video clip is part of another method that I had tried.

Quick Side Note

Some quick geeky technical info about all of this. All materials have property known as coefficient of thermal expansion when subjected to heat and cold. This is the rate that materials expand and contract when heated or cooled. This rate is measured using some really glazed-over math formulas which I would recommend Wiki for the info if you are so inclined.

Now, every material like copper, iron, glass(depending on the formula), etc, have different coefficents. If their coefficients are close enough, then they may be compatible. If their coefficients are too far apart, they will most likely be incompatible.

There are probably hundreds of different glass formulas and most are incompatible with each other.

Normally, just tossing random materials in hot glass will cause the glass to crack when it cools.

The copper wire that I am using is just compatible enough with the base glass I am using that there is not a problem with cracking.

That being said, a large chunk of copper or very thick wire may crack the glass eventually.

Finishing the Simple Circuit

Other then showing a few construction photos, I will not go into how to wire and power LEDs. There are tons of instructables that focus on that.

A Few Last Photos

This page has a few photos and video of another copper circuit encased in glass. This has got a little art nouveau feel to it.